| Good to see you around. :) I've got a few bits to bounce off you on this topic - would love to hear your thoughts... The crankcase ventilation is commonly attributed to enabling the evacuation of blowby gases from the crankcase and given that raw fuel will break down the hydrocarbon chains of oil, it would make sense to minimize this contaminant. But here's what I can't quite get my head around: the PCV system isn't purely a ventilation system in the sense of having both an inlet and outlet for a ventilating medium. It really is just a scavenge system that applies a bit of vacuum to the volume where blowby gases are entering. There is no dilution of the blowby gases - only a small reduction in the density of the gases is occuring due to the small vacuum created by the PCV system. If the PCV system was actually pumping clean atmospheric air into, say hypothetically, one side of the engine and also applying a suction at the other "side" of the engine, given this system produces a reasonable displacement of air, it would dilute the blowby gases and reduce the amount being absorbed by the oil. When I think of the term, "Positive Crankcase Ventilation", I really think of the hypothetical system I described above as it really is a positive displacement configuration and not just a scavenging system. Even still, I really question the advertised value of the PCV system WRT engine longevity by way of cleaner oil... especially when you have other factors such as shearing the oil experiences as it passes through the turbochargers and the like as it holds a plane at the rod bearing journals (which are a bit undersized IMHO). Using high-quality synthetic oil, which was engineered/developed to offer improved performance characteristics over conventional lubes, combined with proper maintenance schedules (i.e. change the goo every 3K miles), and adding to that the simple observations (above) of how the system is designed and functions, I find it difficult to substantiate a claim that eliminating the PCV system will reduce the service life of the engine. I've just seen far too many engines come apart for incredibly simple reasons, like failing fuel pumps, regulator vauum line missing/leaking, overboosting, or overheating.....
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